libubus.c

   1 #include <sys/types.h>
   2 #include <sys/uio.h>
   3 #include <sys/socket.h>
   4 #include <unistd.h>
   5
   6 #include <libubox/blob.h>
   7 #include <libubox/blobmsg.h>
   8 #include <libubox/usock.h>
   9
  10 #include "libubus.h"
  11 #include "ubusmsg.h"
  12
  13 #define DEBUG 1
  14
  15 #ifdef DEBUG
  16 #define DPRINTF(_format, ...) fprintf(stderr, "ubus: " _format, ## __VA_ARGS__)
  17 #else
  18 #define DPRINTF(...) do {} while(0)
  19 #endif
  20
  21 #define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
  22
  23 const char *__ubus_strerror[__UBUS_STATUS_LAST] = {
  24         [UBUS_STATUS_OK] = "Success",
  25         [UBUS_STATUS_INVALID_COMMAND] = "Invalid command",
  26         [UBUS_STATUS_INVALID_ARGUMENT] = "Invalid argument",
  27         [UBUS_STATUS_METHOD_NOT_FOUND] = "Method not found",
  28         [UBUS_STATUS_NOT_FOUND] = "Not found",
  29         [UBUS_STATUS_NO_DATA] = "No response",
  30 };
  31
  32 static struct blob_buf b;
  33
  34 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  35         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  36         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  37         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  38         [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
  39 };
  40 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  41
  42 struct ubus_pending_data {
  43         struct list_head list;
  44         int type;
  45         struct blob_attr data[];
  46 };
  47
  48 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  49 {
  50         const uint32_t *id1 = k1, *id2 = k2;
  51
  52         if (*id1 < *id2)
  53                 return -1;
  54         else
  55                 return *id1 > *id2;
  56 }
  57
  58 struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  59 {
  60         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  61         return attrbuf;
  62 }
  63
  64 const char *ubus_strerror(int error)
  65 {
  66         static char err[32];
  67
  68         if (error < 0 || error >= __UBUS_STATUS_LAST)
  69                 goto out;
  70
  71         if (!__ubus_strerror[error])
  72                 goto out;
  73
  74         return __ubus_strerror[error];
  75
  76 out:
  77         sprintf(err, "Unknown error: %d", error);
  78         return err;
  79 }
  80
  81 static int ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  82                          struct blob_attr *msg, int cmd, uint32_t peer)
  83 {
  84         struct ubus_msghdr hdr;
  85         struct iovec iov[2] = {
  86                 STATIC_IOV(hdr)
  87         };
  88
  89         hdr.version = 0;
  90         hdr.type = cmd;
  91         hdr.seq = seq;
  92         hdr.peer = peer;
  93
  94         if (!msg) {
  95                 blob_buf_init(&b, 0);
  96                 msg = b.head;
  97         }
  98
  99         iov[1].iov_base = (char *) msg;
 100         iov[1].iov_len = blob_raw_len(msg);
 101
 102         return writev(ctx->sock.fd, iov, 2);
 103 }
 104
 105 int ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
 106                        struct blob_attr *msg, int cmd, uint32_t peer)
 107 {
 108         memset(req, 0, sizeof(*req));
 109
 110         INIT_LIST_HEAD(&req->list);
 111         INIT_LIST_HEAD(&req->pending);
 112         req->ctx = ctx;
 113         req->peer = peer;
 114         req->seq = ++ctx->request_seq;
 115         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 116 }
 117
 118 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 119 {
 120         int bytes;
 121
 122         while (iov->iov_len > 0) {
 123                 bytes = read(fd, iov->iov_base, iov->iov_len);
 124                 if (bytes < 0) {
 125                         bytes = 0;
 126                         if (errno == EINTR)
 127                                 continue;
 128
 129                         if (errno != EAGAIN) {
 130                                 perror("read");
 131                                 return false;
 132                         }
 133                 }
 134                 if (!wait && !bytes)
 135                         return false;
 136
 137                 wait = true;
 138                 iov->iov_len -= bytes;
 139                 iov->iov_base += bytes;
 140         }
 141
 142         return true;
 143 }
 144
 145 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 146 {
 147         if (hdr->version != 0)
 148                 return false;
 149
 150         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 151                 return false;
 152
 153         if (blob_raw_len(hdr->data) + sizeof(*hdr) > UBUS_MAX_MSGLEN)
 154                 return false;
 155
 156         return true;
 157 }
 158
 159 static bool get_next_msg(struct ubus_context *ctx, bool wait)
 160 {
 161         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 162
 163         /* receive header + start attribute */
 164         iov.iov_len += sizeof(struct blob_attr);
 165         if (!recv_retry(ctx->sock.fd, &iov, wait))
 166                 return false;
 167
 168         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 169         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 170                 return false;
 171
 172         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 173 }
 174
 175 static bool ubus_get_status(struct ubus_msghdr *hdr, int *ret)
 176 {
 177         ubus_parse_msg(hdr->data);
 178
 179         if (!attrbuf[UBUS_ATTR_STATUS])
 180                 return false;
 181
 182         *ret = blob_get_int32(attrbuf[UBUS_ATTR_STATUS]);
 183         return true;
 184 }
 185
 186 static void ubus_process_req_data(struct ubus_request *req)
 187 {
 188         struct ubus_pending_data *data;
 189
 190         while (!list_empty(&req->pending)) {
 191                 data = list_first_entry(&req->pending,
 192                         struct ubus_pending_data, list);
 193                 list_del(&data->list);
 194                 if (!req->cancelled)
 195                         req->data_cb(req, data->type, data->data);
 196                 free(data);
 197         }
 198 }
 199
 200 static void ubus_req_complete_cb(struct ubus_request *req)
 201 {
 202         ubus_complete_handler_t cb = req->complete_cb;
 203
 204         if (!cb)
 205                 return;
 206
 207         req->complete_cb = NULL;
 208         cb(req, req->status_code);
 209 }
 210
 211 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 212 {
 213         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 214
 215         if (!list_empty(&req->list))
 216                 list_del(&req->list);
 217
 218         ubus_get_status(hdr, &ret);
 219         req->peer = hdr->peer;
 220         req->status_msg = true;
 221         req->status_code = ret;
 222         if (!req->blocked)
 223                 ubus_req_complete_cb(req);
 224
 225         return ret;
 226 }
 227
 228 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 229 {
 230         struct ubus_pending_data *data;
 231         int len;
 232
 233         if (!req->blocked) {
 234                 req->blocked = true;
 235                 req->data_cb(req, hdr->type, hdr->data);
 236                 ubus_process_req_data(req);
 237                 req->blocked = false;
 238
 239                 if (req->status_msg)
 240                         ubus_req_complete_cb(req);
 241
 242                 return;
 243         }
 244
 245         len = blob_raw_len(hdr->data);
 246         data = calloc(1, sizeof(*data) + len);
 247         if (!data)
 248                 return;
 249
 250         data->type = hdr->type;
 251         memcpy(data->data, hdr->data, len);
 252         list_add(&data->list, &req->pending);
 253 }
 254
 255 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 256 {
 257         struct ubus_request *req;
 258
 259         list_for_each_entry(req, &ctx->requests, list) {
 260                 if (seq != req->seq || peer != req->peer)
 261                         continue;
 262
 263                 return req;
 264         }
 265         return NULL;
 266 }
 267
 268 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 269 {
 270         struct ubus_request_data req;
 271         struct ubus_object *obj;
 272         uint32_t objid = 0;
 273         int method;
 274         int ret = 0;
 275
 276         ubus_parse_msg(hdr->data);
 277
 278         if (!attrbuf[UBUS_ATTR_OBJID])
 279                 return;
 280
 281         objid = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 282
 283         if (!attrbuf[UBUS_ATTR_METHOD]) {
 284                 ret = UBUS_STATUS_INVALID_ARGUMENT;
 285                 goto send;
 286         }
 287
 288         obj = avl_find_element(&ctx->objects, &objid, obj, avl);
 289         if (!obj) {
 290                 ret = UBUS_STATUS_NOT_FOUND;
 291                 goto send;
 292         }
 293
 294         for (method = 0; method < obj->n_methods; method++)
 295                 if (!strcmp(obj->methods[method].name,
 296                             blob_data(attrbuf[UBUS_ATTR_METHOD])))
 297                         goto found;
 298
 299         /* not found */
 300         ret = UBUS_STATUS_METHOD_NOT_FOUND;
 301         goto send;
 302
 303 found:
 304         req.object = objid;
 305         req.peer = hdr->peer;
 306         req.seq = hdr->seq;
 307         ret = obj->methods[method].handler(obj, &req, obj->methods[method].name,
 308                                            attrbuf[UBUS_ATTR_DATA]);
 309
 310 send:
 311         blob_buf_init(&b, 0);
 312         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 313         blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
 314         ubus_send_msg(ctx, hdr->seq, b.head, UBUS_MSG_STATUS, hdr->peer);
 315 }
 316
 317 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 318 {
 319         struct ubus_request *req;
 320
 321         switch(hdr->type) {
 322         case UBUS_MSG_STATUS:
 323                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 324                 if (!req)
 325                         break;
 326
 327                 ubus_process_req_status(req, hdr);
 328                 break;
 329
 330         case UBUS_MSG_DATA:
 331                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 332                 if (req && req->data_cb)
 333                         ubus_req_data(req, hdr);
 334                 break;
 335
 336         case UBUS_MSG_INVOKE:
 337                 ubus_process_invoke(ctx, hdr);
 338                 break;
 339         default:
 340                 DPRINTF("unknown message type: %d\n", hdr->type);
 341                 break;
 342         }
 343 }
 344
 345 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 346 {
 347         if (!list_empty(&req->list))
 348                 return;
 349
 350         req->cancelled = true;
 351         ubus_process_req_data(req);
 352         list_del(&req->list);
 353 }
 354
 355 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 356 {
 357         if (!list_empty(&req->list))
 358                 return;
 359
 360         list_add(&req->list, &ctx->requests);
 361 }
 362
 363 static void ubus_handle_data(struct uloop_fd *u, unsigned int events)
 364 {
 365         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 366         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 367
 368         while (get_next_msg(ctx, false))
 369                 ubus_process_msg(ctx, hdr);
 370
 371         if (u->eof)
 372                 ctx->connection_lost(ctx);
 373 }
 374
 375 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req)
 376 {
 377         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 378
 379         if (!list_empty(&req->list))
 380                 list_del(&req->list);
 381
 382         while (1) {
 383                 if (req->status_msg)
 384                         return req->status_code;
 385
 386                 if (req->cancelled)
 387                         return UBUS_STATUS_NO_DATA;
 388
 389                 if (!get_next_msg(ctx, true))
 390                         return UBUS_STATUS_NO_DATA;
 391
 392                 if (hdr->seq != req->seq || hdr->peer != req->peer)
 393                         goto skip;
 394
 395                 switch(hdr->type) {
 396                 case UBUS_MSG_STATUS:
 397                         return ubus_process_req_status(req, hdr);
 398                 case UBUS_MSG_DATA:
 399                         if (req->data_cb)
 400                                 ubus_req_data(req, hdr);
 401                         continue;
 402                 default:
 403                         goto skip;
 404                 }
 405
 406 skip:
 407                 ubus_process_msg(ctx, hdr);
 408         }
 409 }
 410
 411 void ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 412                        struct blob_attr *msg, struct ubus_request *req)
 413 {
 414         blob_buf_init(&b, 0);
 415         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 416         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 417         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 418
 419         ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj);
 420 }
 421
 422 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 423                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv)
 424 {
 425         struct ubus_request req;
 426
 427         ubus_invoke_async(ctx, obj, method, msg, &req);
 428         req.data_cb = cb;
 429         req.priv = priv;
 430         return ubus_complete_request(ctx, &req);
 431 }
 432
 433 static void ubus_publish_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 434 {
 435         struct ubus_object *obj = req->priv;
 436
 437         ubus_parse_msg(msg);
 438
 439         if (!attrbuf[UBUS_ATTR_OBJID])
 440                 return;
 441
 442         obj->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 443
 444         if (attrbuf[UBUS_ATTR_OBJTYPE])
 445                 obj->type->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJTYPE]);
 446
 447         obj->avl.key = &obj->id;
 448         avl_insert(&req->ctx->objects, &obj->avl);
 449 }
 450
 451 static bool ubus_push_table_data(const struct ubus_signature **sig, int *rem, bool array)
 452 {
 453         const struct ubus_signature *cur;
 454         bool nest_type;
 455         void *nest;
 456
 457         while (rem) {
 458                 cur = (*sig)++;
 459                 (*rem)--;
 460                 switch(cur->type) {
 461                 case UBUS_SIGNATURE_END:
 462                         return !array;
 463                 case BLOBMSG_TYPE_INT32:
 464                 case BLOBMSG_TYPE_STRING:
 465                         blobmsg_add_u32(&b, cur->name, cur->type);
 466                         break;
 467                 case BLOBMSG_TYPE_TABLE:
 468                 case BLOBMSG_TYPE_ARRAY:
 469                         nest_type = cur->type == BLOBMSG_TYPE_ARRAY;
 470                         nest = blobmsg_open_nested(&b, cur->name, nest_type);
 471                         if (!ubus_push_table_data(sig, rem, nest_type))
 472                                 return false;
 473                         blobmsg_close_table(&b, nest);
 474                         break;
 475                 default:
 476                         return false;
 477                 }
 478                 if (array)
 479                         return true;
 480         }
 481         return false;
 482 }
 483
 484 static bool ubus_push_object_type(struct ubus_object_type *type)
 485 {
 486         void *s, *m;
 487         int rem = type->n_signature;
 488         const struct ubus_signature *sig = type->signature;
 489
 490         s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
 491         while (rem) {
 492                 if (sig->type != UBUS_SIGNATURE_METHOD)
 493                         return false;
 494
 495                 m = blobmsg_open_table(&b, sig->name);
 496
 497                 sig++;
 498                 rem--;
 499                 if (!ubus_push_table_data(&sig, &rem, false))
 500                         return false;
 501
 502                 blobmsg_close_table(&b, m);
 503         }
 504         blob_nest_end(&b, s);
 505
 506         return true;
 507 }
 508
 509 int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 510 {
 511         struct ubus_request req;
 512         int ret;
 513
 514         if (obj->id || !obj->name || !obj->type)
 515                 return UBUS_STATUS_INVALID_ARGUMENT;
 516
 517         blob_buf_init(&b, 0);
 518         blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 519
 520         if (obj->type->id)
 521                 blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
 522         else if (!ubus_push_object_type(obj->type))
 523                 return UBUS_STATUS_INVALID_ARGUMENT;
 524
 525         ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 526         req.data_cb = ubus_publish_cb;
 527         req.priv = obj;
 528         ret = ubus_complete_request(ctx, &req);
 529         if (ret)
 530                 return ret;
 531
 532         if (!obj->id)
 533                 return UBUS_STATUS_NO_DATA;
 534
 535         return 0;
 536 }
 537
 538 void ubus_default_connection_lost(struct ubus_context *ctx)
 539 {
 540         if (ctx->sock.registered)
 541                 uloop_end();
 542 }
 543
 544 struct ubus_context *ubus_connect(const char *path)
 545 {
 546         struct ubus_context *ctx;
 547         struct {
 548                 struct ubus_msghdr hdr;
 549                 struct blob_attr data;
 550         } hdr;
 551         struct blob_attr *buf;
 552
 553         if (!path)
 554                 path = UBUS_UNIX_SOCKET;
 555
 556         ctx = calloc(1, sizeof(*ctx));
 557         if (!ctx)
 558                 goto error;
 559
 560         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 561         if (ctx->sock.fd < 0) {
 562                 DPRINTF("Failed to connect to server\n");
 563                 goto error_free;
 564         }
 565         ctx->sock.cb = ubus_handle_data;
 566
 567         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
 568                 DPRINTF("Failed to read initial message data\n");
 569                 goto error_close;
 570         }
 571
 572         if (!ubus_validate_hdr(&hdr.hdr)) {
 573                 DPRINTF("Failed to validate initial message header\n");
 574                 goto error_close;
 575         }
 576
 577         if (hdr.hdr.type != UBUS_MSG_HELLO) {
 578                 DPRINTF("Unexpected initial message\n");
 579                 goto error_close;
 580         }
 581
 582         buf = calloc(1, blob_raw_len(&hdr.data));
 583         if (!buf)
 584                 goto error_close;
 585
 586         memcpy(buf, &hdr.data, sizeof(hdr.data));
 587         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf)) {
 588                 DPRINTF("Failed to retrieve initial message data\n");
 589                 goto error_free_buf;
 590         }
 591
 592         ctx->local_id = hdr.hdr.peer;
 593         free(buf);
 594
 595         ctx->connection_lost = ubus_default_connection_lost;
 596
 597         INIT_LIST_HEAD(&ctx->requests);
 598         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 599
 600         if (!ctx->local_id) {
 601                 DPRINTF("Failed to get local peer id\n");
 602                 goto error_close;
 603         }
 604
 605         return ctx;
 606
 607 error_free_buf:
 608         free(buf);
 609 error_close:
 610         close(ctx->sock.fd);
 611 error_free:
 612         free(ctx);
 613 error:
 614         return NULL;
 615 }
 616
 617 void ubus_free(struct ubus_context *ctx)
 618 {
 619         close(ctx->sock.fd);
 620         free(ctx);
 621 }